Mechanisms and devices often have gears which need to be locked into a certain position. One way this has been accomplished is through the radial movement of a locking member into engagement with the gear teeth, as shown in U.S. Pat. No. 1,742,963 to McGlynn. This type of lock relies on the interference of the teeth of the gear lock with the teeth of the gear by positively restricting any movement of the lock away from the gear. The McGlynn positioning mechanism includes a spring-loaded gear locking member having teeth which radially engage the teeth of the circular gear. To rotate freely, the gear would have to bias the gear lock radially, overcoming both the frictional forces between the two surfaces and the biasing force created by the gear lock. Because of the angle at which the gear tooth acts on the gear lock, the gear is effectively locked in place.
This type of gear locking mechanism may not be suitable for some applications. For example, it may not be desirable or even possible to use a gear lock in which the teeth of the lock are prevented from disengagement with the gear teeth by forcing the gear lock against the gear.